http://www.optimumperformanceinstitute.com/bpd-program/root-causes-of-bpd/
Genetic and Biological Indicators
Perhaps one of the most compelling arguments for the role of genetics in borderline personality disorder comes from a large-scale Norwegian study of identical twins that indicated a heritability estimate of 42 percent, as published in Psychiatric Genetics. The study also indicated that the chromosome with the highest linkage rate was chromosome 9. This may indicate a direct familial link and the distinct possibility of BPD being passed down genetically.
Environmental Causes
Childhood events as well as social and cultural surroundings play large roles in personality development and may also serve to facilitate the development of a personality disorder. Unstable family relationships, childhood neglect or abandonment, and exposure to intense and chronic stress and fear as a child seem to play a role in people developing BPD down the road. Early relationships help to form the person you become and what you believe to be normal.
Risk Factors
While it is not completely understood what exactly causes borderline personality disorder and why some people develop the disorder and others don’t, most experts agree on certain risk factors increasing the odds for someone to develop BPD. These risk factors include:
Childhood abuse
Brain abnormalities
Direct relative with a mental health disorder
Hereditary predisposition
